title: The phospholipase A1 activity of lysophospholipase A-I links platelet activation to LPA production during blood coagulation.
abstract: Platelet activation initiates an upsurge in polyunsaturated (18:2 and 20:4) lysophosphatidic acid (LPA) production. The biochemical pathway(s) responsible for LPA production during blood clotting are not yet fully understood. Here we describe the purification of a phospholipase A(1) (PLA(1)) from thrombin-activated human platelets using sequential chromatographic steps followed by fluorophosphonate (FP)-biotin affinity labeling and proteomics characterization that identified acyl-protein thioesterase 1 (APT1), also known as lysophospholipase A-I (LYPLA-I; accession code O75608) as a novel PLA(1). Addition of this recombinant PLA(1) significantly increased the production of sn-2-esterified polyunsaturated LPCs and the corresponding LPAs in plasma. We examined the regioisomeric preference of lysophospholipase D/autotaxin (ATX), which is the subsequent step in LPA production. To prevent acyl migration, ether-linked regioisomers of oleyl-sn-glycero-3-phosphocholine (lyso-PAF) were synthesized. ATX preferred the sn-1 to the sn-2 regioisomer of lyso-PAF. We propose the following LPA production pathway in blood: 1) Activated platelets release PLA(1); 2) PLA(1) generates a pool of sn-2 lysophospholipids; 3) These newly generated sn-2 lysophospholipids undergo acyl migration to yield sn-1 lysophospholipids, which are the preferred substrates of ATX; and 4) ATX cleaves the sn-1 lysophospholipids to generate sn-1 LPA species containing predominantly 18:2 and 20:4 fatty acids.
authors.affiliation: Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Alyssa L
authors.initials: AL
authors.lastname: Bolen
authors.forename: Anjaparavanda P
authors.initials: AP
authors.lastname: Naren
authors.forename: Sunitha
authors.initials: S
authors.lastname: Yarlagadda
authors.forename: Sarka
authors.initials: S
authors.lastname: Beranova-Giorgianni
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Derek
authors.initials: D
authors.lastname: Norman
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Baker
authors.forename: Meng M
authors.initials: MM
authors.lastname: Rowland
authors.forename: Michael D
authors.initials: MD
authors.lastname: Best
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Sano
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Tsukahara
authors.forename: Karoly
authors.initials: K
authors.lastname: Liliom
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Gabor
authors.initials: G
authors.lastname: Tigyi
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000502:physiology*; D006801:Humans; D008245:Lysophospholipase / Q000378:metabolism*; D008246:Lysophospholipids / Q000096:biosynthesis*; D008297:Male; D051379:Mice; D054466:Phospholipases A1 / Q000378:metabolism*; D015539:Platelet Activation / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D008246:Lysophospholipids; D054466:Phospholipases A1; D008245:Lysophospholipase; C032881:lysophosphatidic acid